[ https://issues.apache.org/jira/browse/CASSANDRA-1902?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Pavel Yaskevich updated CASSANDRA-1902: --------------------------------------- Attachment: CASSANDRA-1902-v6.patch Fixed doc string for SegmentedFile.complete() and renamed isRangeInCache() to wasRangeInCache(). I have made changes to NativeMappedSegment.migrateCachedPages() and BufferedSegmentedFile.tryPreserveFilePageCache() so it does not do syscall for each page, instead it collectes continues regions of the cache and does a single call on each to minimise seeking as much as possible. > Migrate cached pages during compaction > --------------------------------------- > > Key: CASSANDRA-1902 > URL: https://issues.apache.org/jira/browse/CASSANDRA-1902 > Project: Cassandra > Issue Type: Improvement > Components: Core > Affects Versions: 0.7.1 > Reporter: T Jake Luciani > Assignee: T Jake Luciani > Fix For: 0.7.5, 0.8 > > Attachments: > 0001-CASSANDRA-1902-cache-migration-impl-with-config-option.txt, > 1902-formatted.txt, 1902-per-column-migration-rebase2.txt, > 1902-per-column-migration.txt, CASSANDRA-1902-v3.patch, > CASSANDRA-1902-v4.patch, CASSANDRA-1902-v5.patch, CASSANDRA-1902-v6.patch > > Original Estimate: 32h > Time Spent: 56h > Remaining Estimate: 0h > > Post CASSANDRA-1470 there is an opportunity to migrate cached pages from a > pre-compacted CF during the compaction process. This is now important since > CASSANDRA-1470 caches effectively nothing. > For example an active CF being compacted hurts reads since nothing is cached > in the new SSTable. > The purpose of this ticket then is to make sure SOME data is cached from > active CFs. This can be done my monitoring which Old SSTables are in the page > cache and caching active rows in the New SStable. > A simpler yet similar approach is described here: > http://insights.oetiker.ch/linux/fadvise/ -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira